Determining Greater Sage-grouse Abundance

Determining Greater Sage-grouse Abundance and Seasonal Landscape Use Patterns on the INL Site

 

Objectives:

  • Track radio-collared sage-grouse from point of capture until the bird dies or the transmitter expires
  • Use telemetry data to develop a spatial model that will characterize nesting, brood-rearing, and winter habitats
  • Document nest locations and monitor nest success
  • Develop statistical models to estimate survivorship and population trajectory.

 

The U.S. Department of Energy, Idaho Operations Office (DOE-ID) recognized that if sage-grouse or other sagebrush-obligate species were listed under the Endangered Species Act, further development and current activities on the INL Site potentially could be delayed or halted to assess the possible effects on sage-grouse. Radio telemetry data gathered from sage-grouse fitted with radio transmission collars will be used to delineate the areas most used by sage-grouse on the INL Site and locate and document nest success.

 

Fifty-two sage-grouse, including 31 hens, have been collared in 2008 and 2009. In 2008, 20 nests were initiated, six of which were successful (30 percent), meaning that at least one egg hatched. Four of the six broods survived until the end of September 2008. In 2009, 24 nests were initiated, 11 of which were successful (46 percent apparent nest success). At least seven of the 11 broods survived until the end of the season in September 2009, and the fates of two broods were unknown. In 2010, five males and six females captured in previous years were still being monitored. Males and females exhibited high lek and nest site fidelity. After a mortality in March, five females were tracked into nesting season, but only one nest was documented.

 

The telemetry study concluded in 2010. Over the two-year study, sage-grouse exhibited high variation in annual distance traveled. Some sage-grouse remained on or near the INL Site year round, whereas others traveled large distances seasonally. The greatest one-way seasonal movements were 108 km (67 miles) and 66 km (41 miles) for a male and female, respectively. After the breeding season and throughout the summer, both males and females tended to disperse off of the INL Site, so that the lowest occurrence of collared sage-grouse on the INL Site was in September.